What is the relationship of consciousness to the neurological activity of the brain? Does the brain behave differently when a person is fully conscious, when they are asleep, or when they are undergoing an epileptic seizure? A recent study by R. Guevara Erra, D. M. Mateos, R. Wennberg, J.L. Perez Velazquez of the University of Toronto, suggests that consciousness if correlated to a maximum number of neurological connections. In thermodynamics, this quantity, describing the complexity of a system, is entropy. In their paper, published in Physics Letters, they write:
It has been said that complexity lies between order and disorder. In the case of brain activity, and physiology in general, complexity issues are being considered with increased emphasis. We sought to identify features of brain organization that are optimal for sensory processing, and that may guide the emergence of cognition and consciousness, by analysing neurophysiological recordings in conscious and unconscious states. We find a surprisingly simple result: normal wakeful states are characterised by the greatest number of possible configurations of interactions between brain networks, representing highest entropy values. Therefore, the information content is larger in the network associated to conscious states, suggesting that consciousness could be the result of an optimization of information processing. These findings encapsulate three main current theories of cognition, as discussed in the text, and more specifically the conceptualization of consciousness in terms of brain complexity. We hope our study represents the preliminary attempt at finding organising principles of brain function that will help to guide in a more formal sense inquiry into how consciousness arises from the organization of matter.
The authors are rightly cautious about the significance of the correlation. Just because A and B are correlated, does not mean that A causes B. However the recognition that a phenomenon such as entropy may describe consciousness opens a new direction for consciousness research.